Give the new balacning a chance. We did that on purpose so that there is actually some fighting, and you don't die in the first 5 seconds of the fight, after walking for 3 minutes from the base to the battle zone.
It's simply not as much fun as before for me. I've decided on this before I even knew 0.3.0 would have such an issue. Yes, I'm long time opposed to games where armor is stronger than weapons. It's also one of the things I didn't like in MW4.
Please, excuse me now as I try to describe as best I can why having too much armor might be bad for my (and maybe other's) enjoyment:
More armor makes it easier to disengage from battle. Being powerless to stop your enemy from getting away is not fun.
Lighter mechs are even more unlikely to defeat bigger ones. Any creative maneuvering they pull won't have much effect. With longer battles, superior firepower and armor will decide who wins. Being stuck with a mech that is unlikely to destroy the enemy isn't fun.
Outnumbered. In any 2v1 or similar situation, the lone pilot is pretty much completely doomed. As it takes longer now to disable or destroy a mech, it is decided beforehand that he'll get swarmed and lose, even if he's elite. Hopelessness is not fun.
And in closing, my best argument: Killing things is fun, more armor makes killing things take longer. Therefore, less fun is had.